The great Jupiter storm is subsiding, says NASA

A comparison image from NASA that shows the gradual reduction in the Great Red Spot's size. Image via NASA

Raging for hundreds of years, one of the largest storms in the solar system appears to be losing steam, according to new images released by US space agency NASA.

Familiar to all as the large moving circle that circumnavigates Jupiter, the anti-cyclonic storm that is up-to three times larger than our whole planet, has been measured to be at its smallest ever recorded size.

Known to scientists simply as the Great Red Spot, NASA scientists have now measured the storm to be approximately 16,500km across.

In comparison, observations as far back as the late 1800s gauged the storm to be as large as 41,000km across, while the Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured it to be 23,300km across.

Beginning in 2012, amateur observations revealed a noticeable increase in the rate at which the spot is shrinking – by almost 1,000km per year – changing its shape from an oval to a circle.

Considering the first recording of the spot was believed to Cassini in 1665, the exact reason for the spot’s demise is still yet to be fully understood, particularly at why the rate of decline has increased so dramatically in recent years.

The photos that confirmed the shrinkage were made by the Hubble Telescope and according to Amy Simon of NASA's Goddard Space Flight Center in the US, the reason may lie in outside forces effectively draining the storm: “In our new observations it is apparent very small eddies are feeding into the storm. We hypothesised these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot."